The Supreme Court’s April 2018 opinion in Oil States was its first ruling on the constitutionality of inter partes review (IPR), with the Court concluding that IPR did not run afoul of Article III and the Seventh Amendment. However, by stating that its holding did not foreclose constitutional challenges on other grounds, the Court set the stage for other such broadsides against the program—one of which has now been addressed by the Federal Circuit. On July 30, the appeals court ruled in Celgene’s challenge of two IPR decisions that the retroactive application of IPR to patents issued before the America Invents Act (AIA) is not an unconstitutional taking in violation of the Fifth Amendment, all but ensuring that IPR will end up before the Supreme Court once again.